1).
Call the number 'N'.
The difference between the number and ten is (N-10).
Twice the difference between the number and ten is 2(N-10).
That's all the question asks for. There's no way to find what number 'N' is.
2).
Call the mystery number 'Q'.
Twice the number is 2Q.
If 5 is subtracted from twice the number, you have (2Q - 5).
But it tells us that the result would be 11 .
So write (2Q - 5) = 7 and solve that simple equation to find what 'Q' is.
3).
Call the mystery number 'Z'.
The quotient of the number and 4 is Z/4.
If you add 5 to the quotient of the number and 4, you have (Z/4 + 5).
It tells us that the result would be 10.
So write (Z/4 + 5) = 10 and solve that simple equation to find what 'Z' is.
4).
I'm sorry. I don't know what this question is asking for.